There are two extracellular beta-lactamases produced by Bacillus cereus 569. One of these enzymes, beta-lactamase I, is inactivated by 6-beta-bromopenicillanic acid: the site of reaction is serine-44. This is a conserved amino acid residue in the other beta-lactamases whose structures have been determined, and it becomes a good candidate for an active-site group in these enzymes. The inactivation may involve a rearrangement leading to a dihydrothiazine. The other extracellular enzyme produced by B. cereus, beta-lactamase II, is exceptional in requiring metal ions for activity. The Zn II and Co II enzymes (the former is more active) have been studied by nuclear magnetic resonance, and by absorption spectroscopy. The groups that bind the metal ion required for activity are three histidine residues and the enzyme's sole thiol group.
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http://dx.doi.org/10.1098/rstb.1980.0050 | DOI Listing |
Probiotics Antimicrob Proteins
January 2025
School of Biosciences and Veterinary Medicine, University of Camerino, Via Gentile III da Varano, 62032, Camerino, Italy.
Growing interests in replacing conventional preservatives and antibiotics in food and pharmaceutical industries have driven the exploration of bacterial metabolites, especially those from strains with generally recognized as safe (GRAS) status, such as lactic acid bacteria (LAB). In this study, a supernatant cocktail derived from multiple LAB strains was prepared and its bioactivities-antimicrobial, antibiofilm, antioxidant, cytotoxicity, and stability-were thoroughly investigated. The cocktail's main components were identified using thermal and protease treatments, gas chromatography coupled to mass spectrometry (GC-MS), and flame ionization detection (GC-FID).
View Article and Find Full Text PDFBiodegradation
January 2025
Centre of Advanced Study in Marine Biology, Faculty of Marine Sciences, Annamalai University, Parangipettai, Tamilnadu, 608502, India.
Pediatr Infect Dis J
January 2025
Wayne State University School of Medicine, Detroit, Michigan.
Microorganisms
December 2024
School of Pharmacy and Medical Sciences, Gold Coast Campus, Griffith University, Gold Coast 4222, Australia.
(Gaertn) Roxb. and Retz. are significant botanicals in ancient Ayurvedic medicine.
View Article and Find Full Text PDFMicroorganisms
December 2024
College of Life Sciences, Northeast Agricultural University, Harbin 150030, China.
Butachlor is a widely utilized acetamide herbicide noted for its systemic selectivity against pre-emergence grass weeds. Butachlor has negative effects on organisms and the environment, so it is necessary to screen degradation strains. In this investigation, strain DC-1 was isolated from soil persistently exposed to butachlor.
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